by Kevin Johnson and David Jackson, USA TODAY

by Kevin Johnson and David Jackson, USA TODAY

Secret Service Director Mark Sullivan announced his retirement Friday after a nearly-three decade career and seven years as head of the agency responsible for protecting the president, vice president and visiting foreign dignitaries.

The decision comes nearly a year after a prostitution scandal during President Obama's trip to Colombia in April.

"I am extremely proud to have had the opportunity to work with the men and women of the Secret Service, and represent an agency so deserving of its reputation as one of the finest law enforcement agencies in the world," Sullivan wrote in an email to the agency.

Sullivan was elevated to director of the agency and its 3,200 agents in 2006 after serving as deputy director and earlier as assistant director for all agency protective operations.

During Sullivan's tenure, he oversaw security for 23 national special events, including the last two presidential inaugurations. President Obama's first inauguration in 2009, which drew 1.8 million people to the capital, was largest gathering in Washington, D.C., history.

"From securing large events such as presidential inaugurations to safeguarding our financial system, the men and women of the agency perform their mission with professionalism and dedication," President Obama said in a statement. "That is a testament to Mark and his steadfast leadership, which will be missed."

Sullivan's term was also marked by scandal when a mix of Secret Service agents and military personnel were implicated for their involvement in procuring prostitutes in Cartagena, Colombia, last April in advance of President Obama's trip there.

In testimony before Congress last year, Sullivan apologized for the conduct of Secret Service personnel in Colombia.

Homeland Security Secretary Janet Napolitano praised Sullivan, saying he epitomizes public service, and "has devoted his life to the safety of our First Families, our nation's leaders, and the public at large."

A native of Arlington, Massachusetts, Sullivan began his Secret Service career as a special agent assigned to the Detroit field office in 1983, after having served for three years as a special agent in the Department of Housing and Urban Development's Office of Inspector General.

In 1991, Sullivan received his first assignment to the Presidential Protective Division, where he served for four years.